No abstract

In Europe an aggressive genetically diverse population of potato late blight is present which regularly causes problems in all potato growing regions. It is therefore of the utmost importance that blight is managed in an integrated way by combining a range of measures. Hygiene measures can keep the number of primary sources of inoculum low. In a number of European countries campaigns are ongoing to increase the awareness of growers to reduce the risk of early inoculum sources such as dumps, volunteers and infected seed. The use of varieties with stable resistance for foliar and tuber blight is also a part of an integrated control strategy. In intermediate resistant varieties possibilities are investigated to reduce the input of fungicides. Fungicides still have a key role to play in the integrated control of late blight. In order to optimize the use of fungicides it is important to know the effectiveness and type of activity of the active ingredients to control blight. The use of fungicides should be targeted by using information on infection conditions based on weather data, disease pressure and fungicide characteristics. Decision Support Systems (DSS) can be used to integrate and organize all the available information required for decisions to control late blight. INTRODUCTIONLate blight was first introduced into Europe in the 1840s and is now the most serious potato disease. Nowadays an aggressive genetically diverse population with both the A1 and A2 mating type is present which regularly causes problems in all potato growing regions in Europe. In this situation the first outbreaks of late blight are detected earlier in the season and the development of the epidemic during blight conducive weather can be faster compared to the pre-1980s situation in which Europe had an asexual genetically similar population. It is therefore of the utmost importance that potato late blight is managed stringently by combining a range of control measures. In this paper some examples are presented of elements that can be part of an integrated control strategy of potato late blight. Measures are described related to the management of primary infection sources as well as the integration of resistant cultivars in the control strategy. Also the optimal use of a wide range of fungicides is presented and some examples of Decision Support Systems used in Europe are presented.